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EPA – PCA Meeting

Monday, July 18, 2011

PCA Office, Washington, DC

11:00 a.m. ‐ 4:00 p.m. EDT

Tentative Meeting Agenda

Dial In: (888) 387‐8686, then 4089494

1) Introductions

2) Review/Discuss Proposed Issue Recommendations

a) Clinker Piles

b) Modifications to the Total Hydrocarbon Standard

c) HCl Monitoring During Start‐up and Shutdown

d) HCl Continuous Emission Monitors Associated with Dry Scrubbers

e) Alternative Particulate Matter (PM) Equation

f) Continuous Monitoring of PM and Mercury During Start‐up and Shutdown

g) Regulatory Status of Various Coal Mill Configurations

h) PM Limit for Modified Sources Under the NSPS

3) Other Issues

4) Other Business

5) Adjourn

Outstanding Issues from June 9, 2011 EPA‐PCA Meeting

July 18 EPA‐PCA Meeting Recommendations

1. Clinker Pile Standards: The basis for the clinker pile standards was discussed at length.  EPA

conceded that the EPA rules resemble those prepared by the South Coast Air Quality

Management District and that, consequently, they would be non‐controversial.  It was

agreed that there was uncertainty regarding the definition of what is an “open clinker pile.”  

It was also explained that, for many plants, clinker piles are not permanent features and are

only present for parts of the year, owing to market dynamics.  It was also acknowledged

that for many plants, their operating permits contain general obligations to minimize
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fugitive emissions at the fence line of the plant, which includes any potential fugitive

emissions from clinker piles.  

Possible Issue Resolution: Rather than employing prescriptive design and management

standards, PCA recommends that EPA rely on, or clarify, as appropriate, the general duty to

minimize emissions from the plant found at Section 63.1348(d).  It was noted that similar

requirements are contained in many Title V permits for individual plants.  Finally, it was

observed that for many plants with these types of Title V permit obligations, they are often

accompanied by “no visible emission standard” imposed at the plant fence line.     

July 18 Recommendation: Eliminate clinker pile design and management standards under

Section 63.1343(c).  Include “open clinker piles” among the list of affected sources under

Section 63.1340(b).  Define “open clinker piles” under Section 63.1341. An “open clinker pile”

is: “an outdoor, unenclosed accumulation of clinker on the ground, which contains in excess of

X tons of clinker, and is utilized for a continuous period in excess of X days.”  In doing the

foregoing, fugitive emissions from open clinker piles would be addressed by the NESHAP

general duty to minimize emissions under Section 63.1348(d).

2. The affirmative defense for malfunctions: This issue was not discussed during the meeting,

as it is being addressed through litigation.

Possible Issue Resolution: To be determined.  

3. Modifications to the THC Standard: The need to modify the THC standard to allow for a

proportional relationship between the THC emission limit and the alternative organic HAP

limit was discussed at length (primarily under the context of the discussion regarding coal

mills).  

Possible Issue Resolution: It was agreed that for plants with THC emissions in excess of 24

ppmv that rely on the alternate organic HAP (oHAP) standard, the plants should be allowed to

scale up the THC emission limit linearly from the measured oHAP concentration to be

equivalent to a 9 ppmv oHAP limit.   

July 18 Recommendation: Plants that opt to comply with the oHAP limit would be allowed to

either:  (1) demonstrate compliance with the oHAP limit annually without having to

continuously monitor THC emissions, or (2) through testing, establish a surrogate THC emission

limit proportional to the 9 ppmv oHAP limit and continuously monitor THC emissions to verify

compliance with the THC surrogate standard.   

4. HCl Monitoring During Start‐up and Shutdown: The difficulty of monitoring HCl emissions

during start‐up and shutdown was discussed, particularly the ability to confirm a 0 ppm

emission limit during these time periods.  EPA acknowledged this difficulty.
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Possible Issue Resolution: EPA appears likely to amend the rule to make the HCl standard

during start‐up and shutdown the same as that which applies during normal operating

conditions, which is currently 3 ppm.   Nonetheless, PCA continues to have concerns generally

about the efficacy of HCl continuous emission monitors.

July 18 Recommendation: EPA should apply at least a 23 ppm (risk‐based threshold) HCl

standard during periods of start‐up and shutdown.  HCl continuous emission monitors during

start‐up and shutdown would be required only for those facilities that DO NOT employ a wet or

dry scrubbing technology (see issue below).  

5. HCl Continuous Emission Monitor (CEM) for Dry Scrubbers: The rule eliminates the

requirement for employing an HCl CEM if the plant is equipped with a wet scrubber.  There

was an extended discussion regarding the merits of applying a similar approach to plants

utilizing a dry scrubber system (e.g., lime injection).   

Possible Issue Resolution: EPA agreed that facilities employing dry scrubbers should also be

given the option of dropping the continuous monitoring obligation in appropriate

circumstances.  It was suggested that a range of percent removal efficiency be identified for dry

systems and that if a plant’s dry system operates within or above the target efficiency (or a

range of efficiencies) that the plant be exempt from the HCl CEM requirement.  Finally, it was

noted that kilns with already low HCl emissions may be able to meet the standard with

relatively low removal efficiencies in the 40‐50% range.  This will be considered when

identifying a potential efficiency range.  

July 18 Recommendation: As indicated above, those facilities equipped with a wet scrubber or

dry scrubbing device (meeting the following criteria) to limit HCl emissions would not be

required to use an HCl CEM.  For dry scrubbers to qualify, cement plant operators would have

to demonstrate that the device when operating is capable of ensuring compliance with the 3

ppm standard during normal operations.   

6. Alternative Particulate Matter (PM) Standard Equation: Discussed at length was the

equation used to compute a site‐specific PM emission limit for those facilities that

commingle cooler and kilns gases.  At issue was how to modify the equation to address

those facilities that also commingle other (primarily coal mill) gases with cooler and kilns

gases.

Possible Issue Resolution: EPA agreed that it makes sense to modify the equation to account

for PM contributions from coal mills.   

July 18 Recommendation: See below:

PM alt = 0.004 x 1.65 x Qs/7000           (Eq. 1)
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PM alt= 0.004 x 1.65 x (Qs + Qb)/7000       (Eq. 2)

Where: 0.004 is the PM exhaust concentration (gr/dscf) equivalent to 0.04 lb per ton clinker

where clinker cooler and kiln exhaust gas are not combined.

1.65 is the conversion factor of lb feed per lb clinker

Qs = Qk + Qc + Qm + Qb  (inputs to the equation based on plant’s gas flow configuration vented

to the main kiln stack, reflecting maximum kiln production)

Qb is the exhaust flow from an alkali bypass stack (dscf/ton raw feed)

Qk is the exhaust flow of the kiln (dscf/ton raw feed)

Qc is the exhaust flow of the clinker cooler (dscf/ton raw feed)

Qm is the exhaust flow of the coal mill (dscf/ton raw feed).

Equation 2 would be used by those plants equipped with a separate alkali bypass stack.

7. Continuous Monitoring for Mercury and PM during Start‐up and Shutdown: Discussed at

length was the difficulty of reliably monitoring mercury and PM emission when the kiln is

starting up and shutting down.  Of concern is the challenge of ever changing flow rates

during these periods.  Also discussed was the seven day rolling average in the rule which is

to be employed for determining compliance during these periods.  EPA agreed that the rule

requirements were potentially confusing and may need modification.   

EPA also understands that duplicate sorbent trap systems may be necessary to comply with

the rule as currently written.  At issue is the difficulty of measuring flow when the kiln is first

starting up cold.  Without an accurate flow measurement, it is impossible to determine

compliance with a concentration based standard.   

As to the seven day rolling average, EPA understands that a single minute should not count

as an entire operating day.  Doing so makes the 7‐day standard much more stringent (in

actuality it becomes a much shorter averaging period).

Possible Issue Resolution: Several potential solutions to this issue were discussed.  One

potential approach may be to include start up and shutdown period within the 30‐day rolling

average employed during normal operating conditions.  Another is to use actual operating time

for the existing 7‐day rolling average, rather than operating days, to capture more data in that

calculation.  Also, a work practice standard may be more appropriate in lieu of a CEM

requirement, owing to the difficulties associated with accurately measuring flow during start‐up

and shutdown.   
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July 18 Recommendation:  [This is under development.]

8. Regulatory Status of Coal Mills: Several cement plant configurations were discussed,

focused on how kiln and clinker cooler gases may be routed to a coal mill to dry the coal.  It

was determined that there are three configurations for the purpose of determining

regulatory compliance, creating a potential approach for resolving this issue, as follows:

Potential Issue Resolution:

a. Coal Mills Receiving Only Hot Air from Clinker Coolers, Vented through a Separate

Stack:  It was agreed that these plants should be regulated by Subpart Y, only for

particulate matter emissions, as the hot air from the cooler is not a product of

combustion.   

b. Coal Mills Receiving Kiln Gases, Vented through a Separate Stack:  It was suggested

that these plants should also be regulated by Subpart Y for particulate matter

emissions, as the kiln gases emanate from an entirely separate heat source.  EPA

noted that it had developed guidance for addressing this circumstance.  

c. Coal Mills Receiving Kiln Gases, Vented  back to the Kiln Exhaust: This configuration,

referred to as an “in‐line coal mill,” would be regulated under Subpart LLL, for both

PM and THC emissions.  It was agreed that there should be negligible HCl and

mercury emissions coming to the kiln from the coal mill.  For PM, as discussed

above, the PM equation should be modified to account to the PM contribution from

the coal mill.  For THC, it was believed that making the relationship between the THC

standard and the organic HAP limit proportional may address any compliance

concern related to THC coming from coal in the coal mill, though this needs

additional thought and consideration.   

July 18 Recommendation: As indicated above, the first two categories of coal mills would be

regulated under NSPS Subpart Y for particulate matter emissions only (Subpart Y PM limit), as

there is no separate combustion source used to dry coal in the mill for these process

configurations.  For the third category of “inline coal mills,” as indicated above under issue 6,

the PM equation for commingled sources would be modified to account for the PM coming

from coal mills and for THC, the oHAP compliance alternative would be employed.

9. PM Limit for Modified Sources under NSPS: While it was acknowledged that this issue is the

subject of litigation, EPA indicated that the agency likely plans to apply the existing source

standard under the NESHAP (0.04 lbs/ton of clinker) to modified sources subject to the

NSPS.    
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Potential Issue Resolution: Apply the existing source NESHAP PM standard to modified sources

subject to the NSPS.  

July 18 Recommendation: Applying the existing source NESHAP PM standard (as modified

through potential rule changes) is preferred to what was in the final NSPS rule, however, this

issue is being litigated and resolution may need to wait the outcome of the DC Circuit decision.